Process of smelting iron ore.



No. 815,016. A PATENTED MAR -13 l906.

P. LJ. HROULT.y PROCESS OP SMEL'I'ING IRON ORE. Arruoulon FILED nur; 14. labs.

INVENTQRI S E S S E N W.. W

top of the furnace mixed with carbon.

' nace sha1 the quantity of carbon necessary to be fed to' UNITED sTATEs PATENT OEEIOE.

- PAUL LOUIS TOUSSAINT HROULT, OF IIA PRAZ, FRANCE, ASSIGNOR TO sOOiETE ELECTRO METALLUROIOUE FRANOAisE, OEIEaOeEs, isERE,

FRANCE, A CORPORATION OF FRANCE.

PROCESS OF SNIELTING IRON ORE.

Specification of Letters Patent.

a Patented March 13, 1906 Application filed June 14, 1905. Serial No. 265,175.y

To all whom t may concern:

Be it known that I, PAUL Louis TOUSSAINT HROULT, a citizen of the Republic of France, residing at La Praz, Savoie, France, have invented certain new and useful Improvements in Processes of Smelting Iron' Ore, of which the following is a specification.

. This invention alms to provide an improved process for the smelting of iron ores to make pig-iron, the particular'aim of the invention being to increase the caloric efficiency of the' carbon used in the smelting. In previous processes the ore has been introduced at the Atv the base of the furnace, Where the greatest heat has been and the reatest chemical' activity, carbon monoxi and carbon dioxid have been formed' in varying proportions. The mixture of gases passing up through the charge has then done very little to reduce the Ore, the carbon mixed throughout the charge radually increasing the percentage of caron monoxid, so that the gases escaping at the top have been largely of carbon monoxid. Thusthe carbon mixed throughout'- the charge has been largely burned to produce a gas having a high potential heat enerig; andA this heat energy has been lost to the nace and only utillzed in external apparatus to,V

" raised.

which the gas has been led.

The aim of the present process is to insure that 'the gas escaping 'at the top ofthe fur- `A be all or as much as possible carvbon dioxidfthat' 1s to say, all the heat units developed by the carbon shallbe developed within the furnace.

by its manner orpoint of introduction `from the CO2 generated in the smelting-chamber. The consequence is a very large reduction in thefurnace. As an example of the most eflicient manner of carrying out the rocess the carbon may be introduced at the ase of the charge and the latter fed into the top of the furnacewithout admixture of carbon, Thus a mixture of carbon monoxid and carbon dioxid will be formed at the base of the furnace, and as this mixture of gases passes upward 5.o through the charge there will be .no further consumption of carbon but a further reduc,- tion of the iron ore andl a oonverslon of` art of the carbon monoxid into d ioxid. t a

The carbon is consumed onlyin the smelting-chamber, being protected certain height, however, the mixture of gases is so diluted with carbon dioxid as to have substantially no further' reducing effect. At this point, as nearly as-it can be determined, additional oxygen will be supplied to the ascending gases and all, or at least a great part, of the remainingmonoxid will be converted into dioxid, the heat produced by the combination serving to heat the charge above. Preferably the heat necessary for melting the iron is supplied by the electric current, so that only so much carbon will be needed as is necessary for effecting the reduction ofthe ore. The higher the point at which the inj ection of oxygen (preferably in the form of air) takes to avoid introducing the oxygen at so low a point as to make the ore above pasty. There 1s no exact limit to the height to which the point of oxidation may be raised though, as stated, the eiiiciency of the injected oxygen becomes less as the point of injection is As an illustration of the economy effected by this process, take one kilo of' iron to be reduced from the ore, (FeZOs). The reduction requires about sixteen hundred and forty calories. To obtain this quantity of heat it is necessary to burn only two hundred grams of carbon to the dioxid, (CO2). In addition the process requires suflicient heat to melt the iron and slag or for one kilo of iron two f hundred and fty calories and for one-half a kilo of slag two hundred and fifty calories, a total of five hundred calories. Two hundred rams of carbon and one horse-power (six hundred and thirtycalories) will therefore 'ef-v fect the reduction and melting and provide an excess of one hundred and thirtycalories for losses by radiation 'and the heat escaping with the gases. pared with"the ordinary process, where one 'kilo of carbon is used in producing'one kilo of iron, i s-' very great. furnace an ordinary furnace be employed heated by carbon injected atthe base, there If instead of an electric'- IOO The economy o f this as com will be required about three hundred grains of carbon in place of the one horse-power in the above example in order to melt the iron and slag, The carbon may beintroduced in any suitable form-such, kfor example, as a pulverized solid-or a liquid or a gas and either pure or mixed with other elements.

I have also designeda furnace which is speciallypadapted to the carrying out of the above process and which is illustrated in the accompanying drawings.

Figure l of the drawingsis a central vertical section. Fig. 2 is a cross-section on the line .2 2 of Fig. 1.

Referring to the specific form illustrated, the furnace is provided with an open upper end to permit the introduction of the ore at. the top vand with tap-holesA A for with drawing the iron and slag at the bottom. Provision is made for introducing the carbon at the bottom by theuse of a hollow electrode B, through which pulverized carbon isforced down by meansof a screw C, driven from a motor D. T-he provision for introducing oxygen comprises nozzles E, passing through the wall Fand preferably of the shape shown in Fig. 2, with orifices G extend'in downward and protected from entrance o 'ore by an overhanging portion H, the nozzle being also provided with a tapered upper edge J to divide thecharge and with a .lower inclined portion K for strength. The electrode B is charge M of ore is introduced at the top and gradually moves 'downward and contains provided with an iron shell L, which burns away at the lower end, but which protects the'electrode vabove the lower end from being eaten away by the carbon dioxid rising through the charge. Vith this furnace the 'substantially' no mixture, of carbon. The

' carbon YN is all'introduced through the hollow protected electrode, preferably in pulvervized form, and forms at the,ba'se a sort of mushroom O, surrounding the lower .end of the electrode and' serving, in fact, as the rIhe molten metal P col.-`

working electrode. lects at the bottom and is drawn off from time to time throu h the tapehole A, as usual. The molten sla-'gv ore is extracted by combining with the carthe ore, taking oxygen there om in 'gradually-diminishing quantities. There being no carbon present in the charge, there is no reduction of the dioxid-to monoxid, such asl takes placein the ordinary furnaces at present generally used. On the contrary,

the full reducing effect of the monoxid is ob floats on the top of the molten metal'P and shades gradually into` the solid charge above; rIhe oxyeen of the tained, and when the mixture of gases is no longer strong enough to extract anysubstantial part of the oxygen from the ore the remaining monoxid is burned by the oxygen entering through the nozzles E and develops a large quantity of heat which heats the portion of the charge above the nozzles, and therefore renders the furnace as a whole more economical.' The oxygen, in the form of' pure oxy en, air, or any gas containing oxy gen, maye forced into the nozzlesE through a ring R surrounding the nozzles.

The improved furnace is not here claimed, being claimed in my copending application, Serial No. 277,466, filed September 7, 1905.

Though I have described with great particularity of detail certain embodiments of this invention, yet it is not to be understood therefrom that the invention is limited to the specific embodiments disclosed.

Various modifications may be made by those skilled in the art without departure from the invention.

1. In the smelting of iron ore, the4 process which consists in feeding the ore, introducing carbon at the base of the charge while prof tecting it from the action of the carbon dioxid .generated by the smelting operation, whereby a mixture of carbon monoxid and carbon dioxidis ,formed of gradually-increasing richness in'carbondioxid as the gases rise to the 'point at which the reduction of ore substantially ceases, and introducing oxygen at such point to further oxidize the carbon monoxid and increase the heating effect in the furnace. Y

2, 'In the smelting of iron ore, the process which consists in feedin(1r the ore, introducing lOC carbon at the base of the charge while protecting it from the action of the carbon dioxid generated by the smeltin operation',l and introducing oxygen ata hig er point to further oxidize the carbon Vmonoxid formed and increase the heating effect in-the furnace.

iron ore, the process- 3. Inthe smelting o which consists in vfeeding the ore, introducing carbon at the base of the charge 'sufficient to produce the chemical reactions necessary While protecting it from the action' of the carbon dioxid generated bythe smeltin operation, and supplying thenecessary means of the passage of an electric current,

,and introducing oxygen at a higher point' to rrL eat by y further oxidize the carbon monoxidformed at the base and to increase the heating effectin thel furnace.A

In Witness whereof I have hereunto si ned my name in the' presence, of two subsc'l'i ing witnesses. 4 p f PAUL Louis TOUSSAINT HROULT.

Witnesses:

DOMINGO A. USINA, 'FRED WHITE, 

